Characterizing Storm Hydrograph Rise and Fall Dynamics With Stream Stage Data1

Abstract: Storm‐flow transients (i.e., hydrograph rise and fall dynamics) may represent an important aspect of understanding streamflow dynamics. However, little is known about how temporal resolution of transient data and climate variability may color these potential indicators of hydrologic pattern or condition. Warm‐season stream stage and rainfall were monitored continuously (5 min) during the 2002 water year in eight tributaries of the Little Miami River (Ohio), which drain 17‐58 km² catchments. Rise rates generated using 5‐min data were different than those generated with mean daily data [calculated with the Indicators of Hydrologic Alteration (IHA) software], though fall rates were similar for fine and coarse temporal data. This result suggests that data with low temporal resolution may not be adequate to fully represent the dynamics of storm rise rates. Conversely, fall rates based on daily stage data (via IHA) were similar to those based on the 5‐min data, and so daily mean data may be appropriate for characterizing fall rates. We next analyzed the possible correlations between rainfall variability and storm‐flow stage dynamics. We derived rise and recession rates from storm stage hydrographs by assuming exponential rise and decay of a runoff peak. We found that raw rise rates (R_raw) were correlated with both the maximum rainfall rate and the time to the centroid of a rain event. We subsequently removed the trend based on these rainfall characteristics, which yielded new representations of rise rates abbreviated as R_rate and R_tcent, respectively, and that had lower variability than the uncorrected (raw) data. Fall rates were found to be independent of rainfall characteristics. Due to the predominant influence of stream hydrology upon aquatic biota and nutrient fluxes, our work suggests that these stage data analysis protocols can refine or otherwise reduce variability in these indices by accounting for relevant factors such as rainfall forcing. These protocols for derivation of transient indices should be tested for their potential to improve correlations between stream hydrology and temporally aligned biotic data and dissolved nutrient fluxes in streams.     

浅谈火电厂烟气脱硫的特许经营模式

介绍了火电厂烟气脱硫特许经营模式（BOOM）发展的必要性和特点,该方式可使国家、火电厂、脱硫公司三方受益。文章还介绍了烟气海水脱硫在国内外的技术进展,列举了火电厂烟气海水脱硫采用BOOM模式的实例。     

浅谈秦皇岛近海海域生态环境保护措施

为了使海域的生态良性循环和海洋资源的可持续发展,本文根据秦皇岛近海海域生态 环境存在的严重问题,从多方面,不同角度,对该海域的生态保护提出了切实可行的保护措施。     

甘肃省农业高质量发展水平测度及制约因子研究

结合农业高质量发展的特征,构建农业高质量发展评价指标体系,采用熵值法、障碍因子诊断模型对甘肃省2009—2018年农业高质量发展水平和制约因素进行分析。结果发现:①2009—2018年,甘肃省农业高质量发展综合水平整体呈增长态势,但农业发展质量不高。②农业绿色发展和农业科技创新是甘肃省农业高质量发展的主要短板。③人力资本和生态环境保护是制约甘肃省农业高质量发展的主要因素。基于研究结果,提出强化政府职能、培育和引进高质量农业人才、贯彻新发展理念、构建生态补偿机制等加快甘肃省农业高质量发展的政策建议。     

对安全人性化需求规律的研究

以人为本是现代安全管理的重要原则,在生产经营活动中,保障人的生命更安全、更健康,生活更幸福,既是安全管理的重要目的,也是人类生活的必然需求.但是,人民提高生命质量的安全需求是多方面的、复杂的.通过对人类生存、繁衍和发展的历史进行深入分析发现,人的安全需求与马斯洛的层次需求理论有相似之处,虽然内涵不同,但需求总是由低层次向高层次发展,当一种低层需求得到满足后,更高层次的需求就占据支配地位,成为人的行为激励因素.笔者从人性化的角度对安全需求层次类型、每一层次的特征、发展规律进行了探讨,其结果有助于安全管理有针对性、科学性、时效性地进行宏观决策和微观调控,也有助于更好地增加安全投入,从而提高安全生产水平.把握人性化需求规律,对保护人们在生产过程中的安全和健康,处理好人的生命价值与安全生产、经济效益、社会效益之间的关系,有重要的现实意义.     

Method of pollution sources assessment in relation to residential site selection

Much investigation supports a high incidence of disease and death rates when people live in ambient polluted air for a long time. Thus, the location of residential sites is important from a public health viewpoint. The method outlined in this paper is useful for determining the location of residential sites based on pollution sources assessment.     

桥丝火工品电极塞在直流激励下的热仿真与计算

目的 获得桥丝火工品电极塞在直流激励下的温升特点,并基于集总参数法,拟合计算桥丝温升.方法 使用 COMSOL 软件仿真计算电极塞的直流加热过程,得到电极塞的温升和温度分布.对仿真温升进行拟合,得到集总参数方程中的桥丝热响应参数.改变激励电流,计算桥丝温升,并与仿真结果比较.结果 在50 mA电流下,桥丝温度呈现由中部向两端降低的趋势,10 ms后,桥丝的平均温升稳定在160 K.桥丝以外区域温度远低于桥丝温度,接近环境温度.对仿真桥丝平均温升拟合得到桥丝热容和热损耗系数分别为1.7967×10-7 J/K和9.2960×10-5 W/K,热时间常数为1.9328 ms.在 70 mA电流下,计算得到的桥丝温升稳定在314 K,并与仿真结果接近.在 50 mA电流下,实际焊点模型的桥丝平均温升较简化焊点模型降低了约26 K,热时间常数降低约0.06 ms.结论 拟合得到了桥丝集总参数方程中的热响应参数,验证了集总参数法在计算桥丝平均温升的适用性.由于脚线温度与环境接近,桥丝热耗散功率基本正比于桥丝温升,与集总参数方程中的热耗散项相符.由于实际焊点模型的桥丝长度增加,导致热容和热损耗系数均增大,而热容增加倍率略大于热损耗系数.     

基于功能安全标准的安全仪表系统可靠性评估软件

介绍了以功能安全国际标准IEC61508和IEC61511工程应用要求为依据,集安全仪表系统的安全仪表功能安全完整性等级(SIL)分配、安全要求规范(SRS)制定、SIL验证、可靠性数据管理等多功能为一体的安全仪表系统可靠性专用评估软件。